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11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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13  * accompanied this code).
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23 
24 import static java.math.BigInteger.ONE;
25 
26 import java.math.BigInteger;
27 import java.util.ArrayList;
28 import java.util.Arrays;
29 import java.util.Collections;
30 import java.util.List;
31 import java.util.Random;
32 
33 /**
34  * @test
35  * @bug 7131192
36  * @summary This test ensures that BigInteger.floatValue() and
37  *          BigInteger.doubleValue() behave correctly.
38  * @author Louis Wasserman
39  */
40 public class PrimitiveConversionTests {
41     static final List<BigInteger> ALL_BIGINTEGER_CANDIDATES;
42 
43     static {
44         List<BigInteger> samples = new ArrayList<>();
45         // Now add values near 2^N for lots of values of N.
46         for (int exponent : Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 31, 32, 33,
47                 34, 62, 63, 64, 65, 71, 72, 73, 79, 80, 81, 255, 256, 257, 511,
48                 512, 513, Double.MAX_EXPONENT - 1, Double.MAX_EXPONENT,
49                 Double.MAX_EXPONENT + 1, 2000, 2001, 2002)) {
50             BigInteger x = ONE.shiftLeft(exponent);
51             for (BigInteger y : Arrays.asList(x, x.add(ONE), x.subtract(ONE))) {
52                 samples.add(y);
y.negate()53                 samples.add(y.negate());
54             }
55         }
56 
57         Random rng = new Random(1234567);
58         for (int i = 0; i < 2000; i++) {
samples.add(new BigInteger(rng.nextInt(2000), rng))59             samples.add(new BigInteger(rng.nextInt(2000), rng));
60         }
61 
62         ALL_BIGINTEGER_CANDIDATES = Collections.unmodifiableList(samples);
63     }
64 
testDoubleValue()65     public static int testDoubleValue() {
66         int failures = 0;
67         for (BigInteger big : ALL_BIGINTEGER_CANDIDATES) {
68             double expected = Double.parseDouble(big.toString());
69             double actual = big.doubleValue();
70 
71             // should be bitwise identical
72             if (Double.doubleToRawLongBits(expected) != Double
73                     .doubleToRawLongBits(actual)) {
74                 System.out.println(big);
75                 failures++;
76             }
77         }
78         return failures;
79     }
80 
testFloatValue()81     public static int testFloatValue() {
82         int failures = 0;
83         for (BigInteger big : ALL_BIGINTEGER_CANDIDATES) {
84             float expected = Float.parseFloat(big.toString());
85             float actual = big.floatValue();
86 
87             // should be bitwise identical
88             if (Float.floatToRawIntBits(expected) != Float
89                     .floatToRawIntBits(actual)) {
90                 System.out.println(big + " " + expected + " " + actual);
91                 failures++;
92             }
93         }
94         return failures;
95     }
96 
main(String[] args)97     public static void main(String[] args) {
98         int failures = testDoubleValue();
99         failures += testFloatValue();
100         if (failures > 0) {
101             throw new RuntimeException("Incurred " + failures
102                     + " failures while testing primitive conversions.");
103         }
104     }
105 }
106